🌎 summit: finish underground

[TheAfroOfDoom]

Summary

@FLOATINGCRETIN finished building, as a first draft. Will likely still have some minor tweaks here and there but this is a good world/schematic candidate for tagging and exporting to the Summit server.

• finished underground/cave
• adjusted player-queue monitors
• decorated ruins-exit hallway (outside)
• adjusted outside pit decorations slightly